Expression of Cystatin C in human stomach neoplasms.

Cystatin C is a member of the cysteine protease inhibitor family and functions to decrease protease production. A recent study showed that it is aberrantly expressed in many malignant tumors in association with tumor invasion and metastasis. Our study aimed to detect Cystatin C expression in stomach neoplasm tissues and adjacent reparative normal tissues. Samples of cancerous and non-cancerous stomach tissue were obtained via surgery as matched pairs from 12 patients with stomach neoplasms and preserved in paraffin. The expression of Cystatin C in the samples was investigated by immunohistochemistry. Fisher's exact test was used to analyze the relationship between stomach neoplasms and adjacent normal tissues. Additionally, mRNA was extracted and analysed by reverse transcriptase-polymerase chain reaction. The intensity of Cystatin C immunostaining was increased in the tumor tissues compared to the adjacent normal tissues. Cystatin C mRNA expression was increased in stomach neoplasms compared to the normal tissues (p<0.05). The results indicate that the expression of Cystatin C may serve as a marker for stomach neoplasms.